Field of the Invention and Related Art Statement
The present invention relates to an apparatus for driving a rectangular card-like record medium such as magnetic card, IC card, and optical card.
In an optical card reading device for reading recorded data from the optical card, a rectangular optical card is moved reciprocally in a longitudinal direction of the optical card, and an optical head including light source, objective lenses, photodetector, etc. is moved in a direction perpendicular to the longitudinal direction of the optical card.
In the known optical card reading device, it has been known to utilize a card holder called a shuttle. That is to say, the optical card is inserted into the shuttle, and then the shuttle is set in the device and moved reciprocally.
In the known card driving apparatus using the shuttle, since the shuttle is very heavy compared with the optical card, it is necessary to use an electric motor of a large size which is expensive and also requires a large power consumption. Further, when the moving direction is inverted, there is produced a rather large mechanical shock, so that the shuttle and thus the optical card could not be moved precisely at a given constant speed. Moreover, the mechanism for moving the heavy shuttle is liable to be complicated in construction and large in size, and thus the whole system tends to be large and expensive.
In order to solve the above mentioned problem, it is considered that the optical card is moved by driving rollers which are directly urged against the optical card. In this case, when the driving rollers are arranged fixedly, it is difficult to move the optical card stably due to the variation in the thickness of particular optical cards and that between respective optical cards.
In Japanese Utility Model Publication No. 51-47,338, there is described the card driving apparatus comprising a guide having a recess formed in one side edge thereof for receiving one side edge of the card, a pair of guide rollers which are resiliently urged against the other side edge of the card, and a pair of driving rollers between which the card is clamped.
There have been proposed various kinds of optical cards having different formats. In one kind of optical card, the optical card has a rectangular contour configuration, a seek area is formed at a middle portion viewed in a longitudinal direction of the card to extend in a width direction perpendicular to the longitudinal direction, and a pair of data areas are formed on respective sides of the seek area. In the seek area, there has been previously recorded various kinds of data for seeking data tracks. When the optical card having the format just explained above is used in the card driving apparatus disclosed in the Japanese Utility Model Publication No. 51-47,338, there might occur the following problem. The data written on the data areas is read out by moving the card reciprocally, so that the card has to be moved over a distance substantially equal to the length of the card. Therefore, when the two guide rollers are separated from each other by a distance substantially equal to the length of the card while an optical head of the reading apparatus is positioned at a middle point between the guide rollers, only one of the guide rollers is urged against the card during the reading of data from a data area. Therefore, the card could not be pressed against the recess of the guide member stably and the data could not be read out accurately due to large focusing and tracking errors. When the guide rollers are arranged closer to each other such that they are always brought into contact with the card, the length of the data areas has to be made small, and thus the memory capacity of the card is limited to a great extent.
In order to avoid the above explained problem, it is considered that a number of guide rollers are arranged along the card traveling path. However, this solution will arise other problems such as complicated construction and increase cost.